There is no question about the urgency to act. Scientists have just told us that, out of nine vital planetary support systems we need to survive, four have exceeded "safe" levels already. Signs of climate change are starting to appear all around us. Plummeting oil prices, meanwhile, are making risky investments, such as Arctic oil, look even more insane.

It's true that global rules for people and planet are needed now more than ever. However, there is no need to wait for any more summits. Summits can help, because they can act as deadlines. They can force governments to find time to pass legislation or get squabbling ministries to agree on a plan. They can provide additional public attention to an issue, which can be an essential agreement to break a political deadlock. We would probably never have achieved this month's step forward for the protection of the High Seas – almost half of our planet – if we hadn't used the Rio+20 Summitin 2012 to give this issue additional political prominence (and a deadline, which was narrowly met).

And summits can also be places where governments send long-term signals to markets. For example, the Paris climate summit in December could agree to bring global carbon pollution down to zero by 2050. That is, at the moment, one option governments are considering. If they adopt it we could see the end of the fossil fuel era. It would certainly make investors in fossil fuels lose some sleep.

We will work for that. And use the two summits this year as opportunities to call for a future without carbon. A future in which all people have electricity – and it's 100% renewable.

The real "opportunities of a lifetime", however, are actual changes catalyzed on the ground. This is what we all must strive for in 2015. And if we do, the good news is that those real changes on the ground increase the likelihood of better global agreements!

The energy revolution, for example, has started already all over the world. 2014 saw China useless coal for the first time this century and install as much solar capacity in one year as the US has ever done. These domestic changes have made it possible for China to pledge that they will stop their relentless rise in climate pollution by 2030 at the latest. That's not good enough – yet – for a safe future. But, if we manage to seriously shift away from coal in China this year – and end the airmagaddon in China's cities – it will not just end unlivable smog for millions of Chinese people. A continued decline in China's coal use would also make it more likely for China to make an even more ambitious pledge internationally...

And that's why we will be taking on coal and supporting renewables all over the world – from India and China to Germany and the United States. Right now, we are focusing on driving back Australia's coal expansion.

If you think financial institutions should not be risking the beautiful Great Barrier Reef for the short-term pursuit of coal join us here.

We must make 2015 a watershed year together. We can make this year count by building movements that force real change, from the Arctic to Australia. We have, as we have headlined in previous campaigns, "No Time to Waste".

But, whatever happens at the big summits this year, we will need all of you to continue pushing for faster and more fundamental changes in 2016. The world will not be saved once and for all in Paris in 10 months. But we can make real progress this year in stopping those who are destroying our planet. We need you to accelerate an energy revolution that delivers for all. We can use the summits as platforms to make that change.

Introducing myself, Daniel Mittler

I am the Political Director of Greenpeace International, heading their Political and Business Unit. I am leading a global team of specialists working on issues ranging from protecting the High Seas to disrupting dirty business models and toxic trade deals. We are responsible for internal strategy advice to campaigns and external representation at global political and business fora. I am a member of the Global Program management team and from September 2014 to June 2015 also managed the Actions and Science Units (two of my favourite parts of Greenpeace). I have also served on the senior management team of Greenpeace’s global forest campaign and on the European Executive Committee.

From 1997-2000 I was a researcher at the Bartlett School of Planning at University College London. I was looking at achieving sustainabilty in cities; mainly because I love cities. The year before, I was living in Bonn serving my country by writing press releases for the youth-wing of Friends of the Earth Germany (BUNDjugend).

Berlin, where I have lived - with a couple of breaks (in Oxford and Amsterdam) - since 2000, is now the (other) place I call home. To be precise: Kreuzberg.

I love kayaking, reading, going to the theatre and cinema, hiking, music (I still try to play the cello) - all the usual middle class stuff. I have a way too loud laugh, but at least I manage to laugh. What really excites me is making the world at the same time a more just and greener place - and creating spaces where people can get active. So, do something!